JPS6241914B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bicycle rear derailleur,
Specifically, the present invention relates to a rear derailleur for a bicycle in which the sealing performance of the guide pulley and/or the bearing portion of the tension pulley to be supported by the tensioner is improved.

A rear derailleur for a bicycle is configured such that a tensioner including two pulleys (upper and lower), that is, a guide pulley and a tension pulley, can be moved in the axial direction of a multi-stage freewheel. The drive chain travels while being suspended in sequence from the tension pulley, the guide pulley, and the first sprocket of the multi-stage freewheel.At this time, when the tensioner is moved in the axial direction of the multi-stage freewheel, it is suspended from the first sprocket of the multi-stage freewheel. The chain that was previously attached is replaced with another sprocket on the side where the tensioner moves.

The above-mentioned guide pulley and tension pulley, on which the drive chain is constantly suspended, have an outer diameter smaller than the smallest diameter sprocket of the multi-stage freewheel, so they are forced to rotate at high speeds, and the tension is not applied to the drive chain. Due to the biasing force of the tension spring that rotates and biases the tensioner to apply the force, and other vibrations, a fairly strong and irregular radial load is applied to the bearing portion of each pulley. Furthermore, since the tensioner is exposed to the outside, dust, dirt, etc. tend to adhere to each pulley. in this way,
The environment surrounding each pulley or its bearing in a tensioner is extremely harsh. Therefore, when dust, dirt, etc. enter, the rotational performance of the bearing, which is forced to rotate at high speed while supporting irregular loads, rapidly deteriorates, and the rotational resistance of each pulley increases, causing problems with the bicycle drive system. This results in a sudden drop in mechanical efficiency.

In all conventional bicycle derailleurs, the bearings of the guide pulley and/or tension pulley have a structure roughly as shown in FIG. 4. That is, the pulley body f is rotatably supported via the bush e on the pulley shaft d, which is supported across the outer frame b and the inner frame c of the tensioner a, and the end of the bush e is held between the pulley shaft d. A pair of side covers g, g are arranged so as to be opposite to each other, and the peripheral edges of the side covers g, g are folded into annular grooves h, h provided on the side surface of the pulley body f.

The structure in which the side covers g, g and the peripheral edges thereof are folded inward and this part is fitted into the annular grooves h, h of the pulley body f is a structure in which the bearing part of the pulley,
In other words, it is intended to prevent dust and water from entering the sliding contact area between the pulley body f and the bushing e, but since the side covers g and the pulley body f rotate relative to each other, dust and water can It has been impossible to completely seal the gap between the side covers g and the pulley body f, which are the paths through which the components enter the sliding contact portion. Therefore, if a bicycle equipped with a conventional bicycle derailleur is repeatedly ridden on rough roads, it is impossible to avoid a sudden deterioration in the performance of the bearings of each pulley portion of the tensioner. Also,
Even if the tensioner was to be disassembled to remove water, dirt, or rust that had entered the pulley bearing, the work was difficult due to its structure.

The present invention solves the above-mentioned problems with conventional bicycle rear derailleurs, and dramatically improves the sealing performance of the tensioner guide pulley and/or tension pulley bearing against mud, dust, water, etc. The main objective is to provide a completely new pulley support structure that can be improved. Another object of the present invention is to provide a pulley support structure that incorporates a lubrication means to improve the rotational performance of the pulley and allows easy maintenance of the lubrication means. .

In order to achieve this object, the present invention takes the following technical measures. That is, a cylindrical shaft part that protrudes toward the opposing frame is formed on the outer frame or the inner frame of the tensioner, and an outer shell part that covers the outer periphery of the cylindrical shaft part with a slight gap between the pulley body and the cylinder. The pulley body is formed to have an inner shaft portion that protrudes into the inside of the shaft portion, and a bearing is interposed between the inner peripheral surface of the cylindrical shaft portion and the outer peripheral surface of the inner shaft portion. It is rotatably supported with respect to the cylinder shaft portion.

By taking such technical measures, the following effects can be achieved.

Since the bearing part is double protected by the outer shell of the pulley body and the cylindrical shaft formed in the frame, it is extremely unlikely that dirt, dust, water, etc. will enter this cylindrical shaft. This improves sealing performance. If a sealed bearing such as a sealed bearing or shielded bearing is used as a bearing, along with the basic structure that prevents dirt from entering the bearing part as described above, the bearing can be completely protected from foreign objects, improving rotational performance. is retained semi-permanently. When the cap is fitted into the cylindrical shaft from the outside, an almost sealed space for grease is formed inside the cap inside the cylindrical shaft, and in this way, the rotation of the pulley can be made even smoother. can. As a result, the pulley main body is supported in a cantilevered manner by the frame on one side, so that disassembly, assembly, or maintenance and inspection of the bearing section can be performed extremely easily.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the entire bicycle rear derailleur according to the present invention. Bicycle rear dayrailer 1
The notch 4 of the bracket 3 that rotatably supports the base member 2 is fitted into a hub axle (not shown) that protrudes outward from a rear end plate (not shown) of a bicycle frame (not shown), and this It is installed by being clamped between the rear end plate and a nut (not shown) screwed into the hub axle. The base member 2 has an adjustment screw 6 for adjusting the rotational position of the mechanism below the base member with respect to the bracket 3 by coming into contact with a stopper 5 provided on the bracket 3.
is screwed in. The tip of the adjustment screw 6 is normally in contact with the stopper 5. As the adjustment screw 6 is screwed in, the base member 2 and below rotate in the direction of the arrow in FIG. 1 about the support shaft 7 connected to the bracket 1.
With this, the bicycle rear derailleur 1 can be adjusted to the most appropriate state according to the length of the drive chain (not shown) and the type of multi-stage freewheel (not shown).

The base member 2 rotatably supports the bases of a pair of parallel link members 8 and 9 extending forward, and a movable member facing the base member 2 is provided at the tip of the link members 8 and 9. 10 is rotatably supported by each of these link members 8 and 9. The base member 2, the pair of link members 8 and 9, and the movable member 10 cooperate to form a so-called parallelogram pantograph link mechanism 11. This parallelogram pantograph link mechanism 11
When the movable member 10 is deformed, the movable member 10 moves while always maintaining a parallel relationship with the base member 2. Thereby, the tensioner 12 attached to the movable member 10 can be moved to a position corresponding to a desired sprocket while maintaining a parallel relationship with each sprocket (not shown) of the multi-stage freewheel. The pantograph link mechanism is deformed by rotating an operating lever at an appropriate portion of the bicycle frame via a double wire whose one end is fixed to the pantograph link mechanism.

The tensioner 12 applies tension to a drive chain (not shown) suspended between a front sprocket (not shown) and one sprocket of a multi-stage freewheel (not shown), and moves the drive chain. This is for replacing the sprocket with the desired sprocket. The tensioner 12 includes two upper and lower pulleys, that is, a guide pulley 13 and a tension pulley 14, which are rotatably supported by a frame 15. The present invention is characterized by the structure for supporting these pulleys 13 and 14 on the frame 15.

An example of a support structure for the pulleys 13 and 14 is shown in FIG.

One of the inner frame 16 and the outer frame 17 that constitute the frame 15, that is, the outer frame 17 in the illustrated example.
A cylindrical shaft portion 18 that protrudes toward the other frame 16 is formed at the cylindrical shaft portion 18 . An inward flange 21 for receiving the inner end of an outer ring 20 of a bearing (in the illustrated example, a ball bearing) 19, which will be described later, is formed at the inner end of the cylindrical shaft portion 18, and an inward collar 21, which will be described later, is formed on the inner periphery of the outer end. cap 22
A screw 23 for screwing is provided.

On the other hand, the pulley body 24 to be supported by the cylindrical shaft 18 is attached to the outer periphery or the inward flange 2 of the cylindrical shaft 18.
A cylindrical outer shell part 26 that covers the outer surface of 1 with a minute gap and has sprocket teeth 25 on the outer periphery.
It is formed into a substantially E-shaped longitudinal section, and has an inner shaft portion 27 that protrudes into the inside of the cylinder shaft portion 18 from inside, and a bottom portion 28 that connects the outer shell portion 26 and the inner shaft portion 27. . However, in the embodiment, the inner shaft portion 2
7 is constructed separately from the outer shell portion 26 to the bottom portion 28 to facilitate assembly.

The pulley body 24 is made rotatable by interposing a bearing 19 between the inner peripheral surface of the cylinder shaft 18 and the outer peripheral surface of the inner shaft 27 of the pulley body 24. Supported.

The above pulley support structure is assembled, for example, as follows.

First, the outer ring 20 of the ball bearing 19a, which is the bearing 19, is press-fitted into the inner circumference of the cylindrical shaft part 18, and the inner shaft part 27 of the pulley body 24 is inserted so that a part of the bottom part 28 is inside the inner ring 29 of the ball bearing 19a. The head screw 30 is inserted into the inner ring 29 until it abuts the end, and then the head screw 30 is screwed into the axial screw hole 31 bored in the inner shaft portion 27, so that the inner ring 29 is connected to the bottom portion 28 and the head screw 30.
and the head 30a of the head 30a. Finally, attach the cap 22 to the screw 23 on the inner circumference of the cylinder shaft portion 18.
Screw into. At this time, the cap 32 and the ball bearing 19
It is very convenient to seal the space defined by the ball bearing 19a and the inner shaft portion 27 with grease in order to maintain the smooth rotational performance of the ball bearing 19a for a long period of time.

In the illustrated example, the inner shaft portion 27 of the pulley main body is constructed separately, but it may of course be constructed integrally.

Further, in the illustrated example, a ball bearing 19a is used as the bearing 19, but other rolling bearings may be used. When using a rolling bearing, so-called sealed bearings such as sealed bearings or shielded bearings may cause grease injected between the inner ring and outer shaft to leak to the outside, or dirt, water, etc. to enter from the outside. This is convenient because the amount is very small. Of course, the bearing 19 may be a sliding bearing using an oil-less metal or other metal as the bearing metal. Even in this case, lubrication can be performed by sealing grease in the space inside the cap 22 as described above, and smooth rotation of the pulley can be sufficiently ensured.

Furthermore, in the illustrated example, the outer frame 17 is configured to support the pulleys 13 and 14;
On the contrary, it may be supported by the inner frame 16.

Furthermore, in the illustrated example, the guide pulley 13
Although the support structure of the present invention is applied to both the tension pulley 14 and the tension pulley 14, only one of them may be provided with the support structure of the present invention, and the other may be of the conventional type.

The present invention is characterized by the support structure of the guide pulley and/or tension pulley, and the structure of other parts of the bicycle rear derailleur does not matter. The applicant of this application has applied for an external transmission for a bicycle in which the pantograph link mechanism in a bicycle derailleur is a sealed type mechanism (Japanese Patent Application No. 153328, No. 1983).
165046, patent application No. 165047 and patent application No. 16504-
No. 167727), but the guide pulley or /
The support structure of the present invention can also be applied to tension pulleys. In this way, all of the important parts of the bicycle rear derailleur are shielded from the outside, making it possible to maximize the functionality of the bicycle rear derailleur and maintain its functionality over a long period of time. It becomes possible.

As explained above, in the bicycle rear derailleur according to the present invention, the bearing part of the pulley can be almost completely sealed from the outside, so that its performance can be dramatically improved and its life can be extended. It has the excellent effect of being able to

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention,
Figure 1 is an overall perspective view, Figure 2 is a sectional view of main parts, and Figure 3 is a perspective view of the whole.
The figure is a perspective view showing the components in an exploded state.
The figure is a reference sectional view showing a conventional example. 1... Bicycle rear derailleur, 12... Tensioner, 16... Inner frame, 17... Outer frame, 18... Cylinder shaft, 19... Bearing, 24... Pulley body, 2
6... Outer shell part, 27... Inner shaft part.

Claims (1)

[Claims] 1. A cylindrical shaft portion is formed on the outer frame or inner frame of the tensioner, and an outer shell portion that covers the outer periphery of the cylindrical shaft portion with a slight gap and an inner shaft portion that protrudes into the inside of the cylindrical shaft portion. For a bicycle, the pulley body having a pulley body is rotatably supported with respect to the cylinder shaft by interposing a bearing between the inner peripheral surface of the cylinder shaft and the outer peripheral surface of the inner shaft. Rear dayrailer.